package PTA.ch03;

import java.util.Scanner;

public class ex09 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        while(sc.hasNextLine()) {
            String str = sc.nextLine();
            String s[] = str.split("\\s+");
            int arr[] = new int[s.length - 1];
            String q = s[0];
            for (int i = 0; i < arr.length; i++) {
                arr[i] = Integer.valueOf(s[i + 1]);

            }
            System.out.println(q+":"+getAvg(arr));

        }
    }
    public static int getAvg(int arr[]){
        int sum=0;
        int count=0;
for(int i=0;i<arr.length;i++){
    sum+=arr[i];
    count++;
}
return sum/count;

    }
}
